This invention relates to an ink jet system of the type which ejects droplets of ink from an orifice.
Various types of ink jet systems are common in the art. One type of system is known as impulse ink jet which employs a transducer suitably energized so as to eject a droplet of ink from the jet on demand. In one form, an impulse ink jet includes a cylindrical tube with an orifice surrounded by a cylindrical transducer. As the transducer is energized to produce a contraction in the cylindrical tube, ink supplied from a reservoir is ejected from the orifice.
It has been generally observed that transducer-driven ink-jets of apparently identical construction do not all operate over a single operating voltage range. This variation in operating voltage may result from such factors as variations in transducer material from piece to piece, variation in the acoustic coupling between the transducer and the remainder of the jet, or from other variations in structure which are not simple to control on a dimensional basis.
These variations are troublesome in a manufacturing environment because they require the transducer driving electronics be tuned to the jets on an individual basis where variations in transducer performance alone can be of the order of 15% to 20%. The problem is made more complex by the fact that the operating life time of the jet in a marketable product is generally far shorter than the life time of the transducer driving electronics. As a consequence, the jet must be field-replaceable and compatible with the existing electronics where the electronics must be capable of being tuned to the jet--an option which would add to the cost of the driver electronics and would require services of a trained field representative.